Tottenham manager Mauricio Pochettino has a dilemma ahead of Saturday's FA Cup semifinal against Chelsea. In January, Spurs sealed a landmark win against Chelsea by mirroring Antonio Conte's three-at-the-back formation, and the system has helped the Premier League's second-placed side produce some of their best performances of the season. However, in the past three games Pochettino has reverted back to the 4-2-3-1 system he used for most of last season, producing 4-0 wins against Watford and Bournemouth.

Here, ESPN FC's Tottenham correspondent Dan Kilpatrick and blogger Ben Pearce make cases for using each system at Wembley.

Dan Kilpatrick: Spurs should revert to 3-4-2-1

Tottenham's 2-0 win in January set the blueprint for how to beat Chelsea. Victor Wanyama and Mousa Dembele won the midfield battle against N'Golo Kante and Nemanja Matic, allowing Spurs to control possession and get the ball to their rampaging wing-backs. The solid base provided by the midfield and centre-backs freed Christian Eriksen, Dele Alli and Harry Kane from defensive duties, and Alli finished Eriksen's crosses for both the goals. It worked -- and this is how Spurs should play against Chelsea again on Saturday.

Pochettino has reverted to a back four in the past three matches and Spurs have been unstoppable, but that's largely because Wanyama was injured at Burnley -- not because the three-at-the-back system was not working. The teams they have beaten -- Swansea, Watford and Bournemouth -- are nowhere near Chelsea's level and, crucially, do not play with three centre-backs like the Blues. Spurs have only lost when playing four centre-backs against a team with wing-backs, so why take that risk for such a high-stakes match?

Admittedly, Danny Rose, injured on Saturday, played in January's win, but Ben Davies is a capable deputy and given his vulnerability one-on-one, it makes sense to negate his defensive responsibilities, particularly against Eden Hazard and Pedro. Wanyama has missed the past three matches, although he returned from the bench against Bournemouth, but he is a player for the big occasions and a steadying presence needed for a semifinal. With him in midfield and Eric Dier in defence, you would bet on Spurs keeping another clean sheet.

The switch would surely see Son Heung-Min lose his place, which would be harsh after eight goals in six games. But some of the South Korea international's best performances this season have come from the bench, notably against West Ham, Southampton and Manchester City, and he can be a hugely effective substitute at any score.

Pochettino is fond of saying that he is focussed only on his own team, but if Manchester United's win over Chelsea on Sunday and Spurs' victory in January prove anything it is that adapting to the opposition can be crucial.

Spurs beat Chelsea 2-0 in January using a 3-4-2-1 system, having previously lost November's meeting at Stamford Bridge 2-1 when operating in a 4-2-3-1 formation. However, other factors have to be considered this time around.

Each team had home advantage when they won and Pochettino was forced to field a heavily weakened back four when his side were defeated at Chelsea. The influential Toby Alderweireld was missing and so were left-backs Rose and Davies, so Kevin Wimmer had to fill in at full-back. Tottenham nonetheless took a 1-0 lead that night and Jan Vertonghen said recently: "Our first half there was maybe the best of the season." With a full-strength rearguard, the visitors may well have held onto their lead or even increased it and won that fixture, too.

The switch to a 3-4-2-1 was undoubtedly a success, but when Spurs beat Chelsea at the turn of the year they had Rose at left-wing-back. This weekend they do not and, while Davies has done a decent job as an understudy, he is ill-suited to having the whole left flank to himself. He lacks the pace to turn into a de facto winger in the final third, as Rose and Kyle Walker are able to do. The recent move back to a 4-2-3-1 has enabled Pochettino to pick a third attacking midfielder instead, and Son has been a valuable addition to the starting lineup.

Son has scored eight goals in six matches and Spurs now have a deadly front four with the South Korea international, Eriksen, Alli and Kane. But a move back to a 3-4-2-1 to match Chelsea's formation would necessitate dropping one member of that quartet, swapping an in-form goal threat for a third centre-back and leaving Davies to provide most, if not all, of the width on the left side.

Things have changed since January. The absence of Rose means the blueprint for that victory over the league leaders might not be so successful this time, while Son's form and importance to Spurs' recent goal glut must also be considered.

Those suggesting Pochettino should return to the plan that last beat Chelsea and opt for a 3-4-2-1 may well ask, "why change a winning formula?" But those who have witnessed the devastating 4-0 victories over Watford and Bournemouth in the past fortnight can easily pose the same question.